1. Field of the Invention
The present invention relates to a cartridge for a game machine. In particular, the present invention relates to an improved cartridge for a game machine, such as a memory cartridge or the like to be mounted in a detachable manner to a game machine (e.g., a video game machine or a hand-held game machine), the improvement being to alleviate unwanted radiation of electromagnetic waves.
2. Description of the Background Art
A game machine such as a video game machine or a hand-held game machine may operate in conjunction with a memory cartridge such as a ROM cartridge or a RAM cartridge which is detachably mounted to the game machine. A memory cartridge or other cartridge for a game machine is likely to cause unwanted radiation (i.e., external leakage) of electromagnetic waves of 10 MHz or above, especially as increasingly higher CPU clock frequencies are used in the game machine. Such unwanted radiation may unfavorably affect surrounding electronic devices including CPUs (e.g., those used in computers, portable information terminals, and pacemakers), and therefore is a potential cause for the malfunctioning of such devices. Entities such as the FCC (Federal Communication Commission) of the U.S. provide regulations against such unwanted radiation of electromagnetic waves, while the VCCI (Voluntary Control Council For Interference By Information Technology Equipment) of Japan provides recommendations concerning the same.
In order to prevent unfavorable influences on surrounding electronic devices and to alleviate unwanted radiation, conventional cartridges for a game machine typically include a metal shield plate, such that a portion of the shield plate is electrically connected to a grounding terminal on a substrate in the cartridge. The grounding terminal serves to absorb the unwanted radiation via a grounding terminal of a connector within an associated game machine.
However, merely introducing a shield plate within the cartridge and electrically connecting it to a grounding terminal of the game machine via a grounding terminal of a connector within the game machine does not sufficiently alleviate unwanted radiation of electromagnetic waves. Moreover, the influence of unwanted radiation of electromagnetic waves increases as the CPU clock frequency used in the game machine is increased.
Therefore, an object of the present invention is to provide a novel cartridge for a game machine which can alleviate the influence of unwanted radiation of electromagnetic waves.
Another object of the present invention is to provide a cartridge for a game machine which can alleviate the influence of unwanted radiation of electromagnetic waves by utilizing a simple and inexpensive construction.
A further object of the present invention is to provide a cartridge for a game machine which addresses the problem of unwanted radiation of electromagnetic waves, and which allows for easy assembly, excellent mass producibility, and low production cost.
The present invention has the following features to attain the above object.
A first aspect of the present invention (claim 1) is directed to a cartridge for a game machine, the cartridge being detachably mountable to a game machine having a connector and a grounding terminal in connection with a recess for receiving the cartridge, the cartridge comprising: a housing, a substrate, a semiconductor element, and a shielding element. The housing includes an upper half and a lower half, and has an open end face at which to mount the cartridge to the connector in the game machine. The substrate is accommodated in the housing, and has an external connection terminal exposed through the open end face, a circuit pattern, and a ground electrode. The semiconductor element (such as a memory) is mounted on the substrate. The shielding element is accommodated within the housing, covers a substantial portion of at least one principal face of the substrate, and is electrically connected to the ground electrode. The housing has an opening in a principal face facing the ground electrode on the substrate and the shielding element to allow the shielding element to be partly exposed through the opening. The shielding element has a shield convex, the shield convex protruding and being exposed through the opening.
Thus, when the cartridge is mounted in the recess, the shield convex is electrically connected to the ground electrode through the opening, thereby removing unwanted radiation of electromagnetic waves occurring on the substrate.
In one embodiment (claim 2), the opening in the housing has a substantially band-like shape extending along a side of the housing. The shield convex is shaped so as to correspond to the substantially band-like shape of the opening.
In another embodiment (claim 3), the shielding element is formed of a plate metal of a conductive material, a portion of which is bent to integrally form the shield convex.
In still another embodiment (claim 4), the opening and the shield convex are formed near a leading end of the cartridge with respect to a direction of inserting the cartridge into the recess, such that the opening and the shield convex extend along a direction perpendicular to the insertion direction.
In still another embodiment (claim 5), the housing includes at least one positioning member on the inside of at least one of the upper and lower halves, the at least one positioning member being for positioning the substrate and the shielding element.
In still another embodiment (claim 6), the cartridge further comprises: a further shielding element being accommodated on the inside of another principal face of the housing so as to face the substrate. The shielding element and the further shielding element are electrically connected to each other within the housing.
In still another embodiment (claim 7), the open end face of the housing is dimensioned so that the housing has a width which is substantially the same as a width of the substrate and that the housing has a thickness which is greater than a thickness of the substrate. The cartridge further comprises a spacer, the spacer being accommodated within the housing to enclose the open end face where the open end face has a thickness greater than the thickness of the substrate.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.